Sarsia_87_83-90.pdf (337.1Kb)

The mortality rates estimated in central North Sea fiSheries iBcreased considerably since 1960~ and also in the total North Sea, as appeared from catch curveso

No catch-at-age data were available for the commercial effort series and the catch-at-age data used in the tuning were estimated from the catch data per fleet

On a total i{orth Sea basis the mean catch per square fits a negative binominal distribution and consequently the geometric mean of the catch-rates in each

Catch statistics of mackerel have not been reported with reference to areas comparable to the new economic zones in the North Sea. Estimates of the catch

The mixed fishery approach may be of relevance for the main target species in commercial fishery cod, herring and sprat. They form about 95 % of the total catch. Pelagic fisheries

Also, sprat catch rates in the German Democratic Republic bottom trawl survey could be considered in this context, but these data were not available to this

the survey indices do not correspond exactly to the stock concept of the catch-at-length analysis. Estimates of stock numbers and fishing mortality rates by this method

Ireland: The majority of the commercial catch (>90%) is assumed to be comprised of lSW salmon. However, an assessment of the sea age of the catch has not been carried